1. Field of the Invention
This invention relates to a material handling car and track assembly and is directed more particularly to direction control means for directing the car along a selected one of a plurality of track avenues.
2. Description of Prior Art
A number of mechanisms have been devised for switching of track supported cars between alternative paths. In U.S. Pat. No. 3,626,857, issued Dec. 14, 1971 to A. G. Omar, there is disclosed a pivotally moveable track section which may be moved to place tracks thereon in alignment with a selected distal track section. Omar also discloses another mechanism wherein one of a plurality of selected switch tracks is raised into a gap between a base track and a selected distal track. The plurality of switch tracks is interconnected such that when a selected switch track is raised to fill the aforesaid gap, the remainder of the switch tracks are necessarily held below the level of the gap, so that only one switch track at a time can occupy the gap.
In the U.S Pat. No. 3,847 086, issued Nov. 12, 1974 to Ulf Steenbeck, there is disclosed a suspended railway system in which switch tracks are immoveably disposed with each switch track section having thereon a plurality of paths. Each of the paths is provided with electromagnetic means which guide a car onto a selected path in the switch track section, and thereby onto a selected distal track section.
A U.S. Pat. No. 4,484,526, issued Nov. 27, 1984 to Yukio Uozumi, there is disclosed a switching system in which the car supporting tracks remain immoveable, and a guide rail adapted for guiding guide wheels of the car includes moveable guide rail switch sections which are vertically moveable into and out of active position in the guide rail.
U.S. Pat. No. 3,628,462, issued Dec. 21, 1971, to William J. Holt discloses a track system for suspended vehicles. The system utilizes horizontal guide rollers on a car which engage a vertical surface of a channel structure. Each car is provided with guide rollers on each side of the car. The car is provided with a solenoid which operates armature elements to raise the guide rollers of one side or the other. The guide rollers are disposed on both ends of a single crankarm which is acted upon by the armature elements. The crankarm is pivotally mounted such that when the guide roller on one side is raised to actively engage the channel structure, the other guide roller on the other side is necessarily removed from engagement with the channel structure.